Apparatus for moistening printing plates in printing machines



m MM 0 5 6/ 2 Myw 5 u M 2 Va a N u f C ffl 2m EE G w m .HA m I I X m MyN no I 4 Mm@ Tmw EP. RG5 Em STQOv UmF www Gn MMF N E T S I o M D.\. O FS U T A m P P A Dec. 23, 1952 Patented Dec. 23, 1952 APPARATUS FORMOISTENING PRINTING PLATES IN PRINTING MACHINES Max Hauser, Zurich, andErnst Wagner, Kusnacht, by Zurich, Switzerland; said Hauser assignor tosaid Wagner Application February 5, 1949, Serial No. 74,726 InSwitzerland October 6, 1948 1 Claim.

The present invention relates to a process for moistening printingplates in printing machines and relates also to apparatus for carryingout this process.

According to the present invention the process consists in blowingcompressed air through a sieve which is wetted with liquid periodically,or with rotary presses, continuously. This process enables finelydivided liquid to be obtained which is deposited uniformly on theprinting plates.

The invention will be further described by way of example, withreference to the accompanying diagrammatic drawings in which:

Fig. 1 shows an apparatus for carrying out the process mentioned. In itthe parts essential for understanding the invention are shown in crosssection.

Fig. 2 shows a detail of an alternative form.

I designates a cylinder carrying printing plates 2, to which cylinderthe plates are fastened in a known manner (not shown) The highest colourroller is denoted by the numeral 3. A casing 4 is fitted before thecylinder I. In this casing a shaft 5 is rotatably mounted concentricallywith the casing. This shaft carries on arms 6, an arc shaped curvedframe 1 which is covered lwith a ne meshed sieve 8. This frame 1 can, asshown in the drawing, be contained in a liquid container 9. The latteris bounded outwardly by the wall of the casing A and inwardly by a wallI running parallel thereto and at its lower end by a closing wall Il.The depth of the container Il is such that the frame 1 can be completelyimmersed therein.

outwardly of the casing `II an intercepting plate 1 I2 is provided whichis connected to a liquid supply pipe I4 by means of a pipe I3. On theinside of the container 9 is arranged a pressure air pipe I5 which isconnected to two pipes I1 through a rst header I6, and thence to threepipes I9 through a second header I8, and finally to a nozzle head 20.The latter is provided with nozzles 2|, the apertures of which can beregulated by spindles 22. Compressed air supplied through the pipe I5 istherefore fed through the different pipes and headers to the nozzles 2|,and thereafter is blown through that part of the sieve in front of thenozzles, so that liquid adhering to the sieve is carried along and blownon to the cylinder 2. To enable the liquid to escape from the casing, aslot 23 is provided in the latter. Liquid falling down is intercepted bythe plate I2 and led back to the supply pipe I4 which is connected to aliquid container or the like, in a manner not shown.

By suitable means (not shown) the arms 6 and with them the frame 1, andthe sieve 8 are periodically lifted in the direction of the arrow I andallowed to fall in a direction opposite to the direction of this arrow.The nozzles could of course be given any periodical movement, forinstance in lateral direction.

Advantageously, the apparatus is so regulated that the sieve is raisedfrom the completely depressed to the completely raised position duringthe same period in which the plate bearing parts of the cylinder movepast the mouths of nozzles 2|.

Depression of the sieve 8 follows accordingly during the period in whichthe part of the cylinder not provided with plates moves past the nozzles2 I.

The sieve 8 is very fine meshed and consists of canvas. The number ofthe nozzles 2| is chosen to suit the apparatus being used; in practice,several nozzles per inch are provided. These are individually regulableand individual nozzles can be completely cut off also, so that thewetting of the plates in any single case can be regulated.

The sieve 8 is preferably detachable and replaceable by another sievelso that a sieve can be used, the mesh of which is well suited to thenature of the plates 2.

In the modification shown in Fig. 2, pipes I9, nozzle head 20, nozzles2|, and spindles 22, correspond with the same parts indicated by thesame numerals in Fig. 1. A straight frame 28 is covered with a finemeshed sieve 29. About a point 25, a lever 26 is oscillatable. Point 25is displaceable along said lever 26. Oscillation of lever 26 is effectedby displacement of a link 21. The displacement of link 21 is effected bymeans not shown. With a constant amount of movement of the link 21,variation of the pivot point 25 varies the amplitude of the motion ofthe sieve 29, with a consequent change in the amount of liquid sprayedtherethrough.

We claim:

In a moistening device for use with a rotary cylinder of a printingpress carrying a printing plate, a sieve in the shape of a segmentalcylindrical surface of a length approximating the width of the plate tobe moistened, a liquid container, means for oscillating said sieve on anaxis corresponding to the axis of the cylindrical surface and parallelto the printing cylinder, said means `being adapted to oscillate thesieve in timed relation to the printing cylinder rotation between oneposition in which the sieve is submerged in said liquid, and another inwhich it is withdrawn from the liquid, and a series of compressed airnozzles arranged along the adjacent to the inner surface of said sieveand directed towards said printing plate.

MAX HAUSER. ERNS'Il WAGNER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 841,142 Gramlich Jan. l5, 19072,101,202 Stevens Dec. 7, 1937 2,389,730 Ilec Nov. 27, 1945

